Exam Prep Chapter 19 Cardiovascular System Heart

Anatomy & Physiology, 3e (McKinley)

Chapter 19 Cardiovascular System: Heart

1) The main functions of the cardiovascular system include the transport and exchange of respiratory gases, nutrients, and wastes throughout the body.

2) The units for perfusion of blood are typically

A) grams per minute.

B) milliliters per minute per gram.

C) milliliters per hour per kilogram.

D) liters per gram.

E) beats per minute per gram.

3) Occlusion of blood vessels tends to lead to

A) increases in perfusion.

B) increases in capillary exchange.

C) inadequate blood supply and damage to body tissues.

D) defibrillation of cardiac muscle cell contraction.

4) Which can be used to characterize blood flow in the human body?

a: There is a unidirectional blood flow.

b: Arteries always carry oxygenated blood.

c: Veins always carry deoxygenated blood.

d: Arteries carry blood away from the heart.

e: Veins carry blood toward the heart.

A) a, c, d, e

B) a, b, c, d, e

C) a, d, e

D) b, c, d, e

E) d, e

5) The pulmonary trunk receives blood from the right ventricle and conducts it toward the lung.  The pulmonary trunk is a(n)

A) artery.

B) capillary.

C) vein.

6) Arteries carry blood toward the heart, while veins carry blood away from the heart.

7) The receiving chambers of the heart are the atria, and the forcefully pumping chambers of the heart are the ventricles.

8) Which carries oxygenated blood from the lungs to the heart?

A) Pulmonary arteries

B) Pulmonary veins

C) Pulmonary trunk

D) Inferior vena cava

E) Superior vena cava

9) Which circuit of the cardiovascular system is responsible for sending blood to the kidneys, stomach, and pelvic regions?

A) Pulmonary circuit

B) Visceral circuit

C) Coronary circuit

D) Systemic circuit

10) Which of the cardiovascular system's circuits has deoxygenated blood in its arteries?

A) Pulmonary circuit

B) Visceral circuit

C) Coronary circuit

D) Systemic circuit

11) Which circuit of the cardiovascular system includes the left ventricle and aorta?

A) Pulmonary circuit

B) Cardio circuit

C) Coronary circuit

D) Systemic circuit

12) Which heart chambers contain deoxygenated blood?

A) Left atrium and right atrium

B) Left ventricle and right ventricle

C) Right atrium and right ventricle

D) Left atrium and left ventricle

E) Right atrium and left ventricle

13) The inferior, conical end of the heart is called the ________.

14) Which pair is located more anteriorly in a heart in normal position?

A) Left atrium and left ventricle

B) Left atrium and right ventricle

C) Right atrium and left atrium

D) Right atrium and right ventricle

E) Right atrium and left ventricle

15) The base of the heart faces in the ________ directions.

A) anterior and inferior

B) anterior and superior

C) posterior and superior

D) posterior and inferior

E) None of these choices is correct.

16) Which correctly describes the heart's apex?

A) Projects slightly anteroinferiorly toward the left side of the body

B) Projects slightly anteroinferiorly toward the right side of the body

C) Projects slightly posteroinferiorly toward the left side of the body

D) Projects slightly posteroinferiorly toward the right side of the body

E) Projects slightly posteroinferiorly toward the midline of the body

17) The term "epicardium" is another name for the

A) visceral layer of the serosal pericardium.

B) parietal layer of the serosal pericardium.

C) external layer of the fibrous pericardium.

D) myocardium.

E) mediastinum.

18) The serous fluid within the pericardial cavity works to

A) lubricate membranes of the pericardium.

B) slow the heart rate.

C) equalize the pressure in the great vessels.

D) eliminate blood pressure spikes.

E) All of the choices are correct.

19) The pericardial cavity is between the

A) heart muscle and serous pericardium.

B) fibrous and serous layers of the pericardium.

C) visceral and parietal layers of the serous pericardium.

D) parietal and myocardial layers of the fibrous pericardium.

20) Which layer is made of dense irregular connective tissue?

A) Myocardium

B) Fibrous pericardium

C) Epicardium

D) Serous pericardium

E) Endocardium

21) The pericardium helps prevent overfilling of the heart and it lessens the friction of movements during heartbeats.

22) The atria are separated from the ventricles externally by the

A) anterior interventricular sulcus.

B) posterior interventricular sulcus.

C) sinoventricular sulcus.

D) coronary sulcus.

E) None of the choices is correct.

23) The posterior interventricular sulcus

A) is another name for the coronary sulcus.

B) contains the great cardiac vein and coronary sinus.

C) is a groove between the ventricles on the back of the heart.

D) is a valve in the interventricular septum that closes at birth.

24) Each of the receiving chambers of the heart has a wrinkled flaplike extension; the one that is more visible from an anterior view is the

A) interatrial septum.

B) interventricular septum.

C) left auricle.

D) right auricle.

25) From which view is the connection between the pulmonary veins and the heart most visible?

A) Anterior view

B) Posterior view

26) The layer of the heart wall composed of cardiac muscle tissue is the

A) pericardium.

B) myocardium.

C) endocardium.

D) pericardial cavity.

E) pectinate muscle.

27) Which describes the endocardium?

a: Has single layer of epithelium

b: Has layer of areolar connective tissue

c: Epithelial cells are squamous

d: Epithelial cells are cuboidal

e: Has layer of adipose connective tissue

f: Has patches of myocardium

A) a, b, c

B) a, b, d

C) a, d, e

D) a, b, c, e

E) a, e, f

28) Deep to the interventricular sulci is the thick muscular wall that divides the left and right ventricles, known as the interventricular ________.

29) The fossa ovalis appears just above the opening of the coronary sinus within the

A) left atrium.

B) left ventricle.

C) right atrium.

D) right ventricle.

30) The papillary muscles attach to the cusps of the atrioventricular valves by means of the

A) pectinate muscles.

B) trabeculae carneae.

C) conus arteriosus.

D) tendinous cords.

E) tricuspid valve.

31) The internal wall surface of each ventricle displays large, smooth, irregular muscular ridges called

A) conus arteriosus.

B) atrioventricular opening.

C) trabeculae carneae.

D) tendinous cords.

E) pectinate muscles.

32) Pectinate muscles are found on the

A) posterior wall of the right ventricle.

B) anterior wall of the right ventricle.

C) internal walls of the right and left atria.

D) posterior walls of the right and left ventricles.

E) external wall of the right atrium.

33) Which are functions performed by the fibrous skeleton of the heart?

a: Separates the atria and ventricles

b: Anchors the heart valves

c: Provides electrical insulation between the atria and ventricles

d: Provides the framework for the attachment of the myocardium

e: None of these are true functions of the fibrous skeleton of the heart

A) a, d

B) b, d

C) a, c, d

D) a, b, c, d

E) e

34) Which feature permits the compression necessary to pump large volumes of blood out of the ventricles?

A) Negative pressure inside the ventricles

B) Absence of oxygenated blood in the atria

C) Arrangement of cardiac muscle in the heart wall

D) Presence of skeletal muscle tissue in the heart skeleton

E) Presence of papillary muscles in the ventricles

35) Which are differences between cardiac muscle tissue and skeletal muscle tissue?

a: The sarcoplasmic reticulum in cardiac muscle is less extensive.

b: The sarcoplasmic reticulum in cardiac muscle is more organized.

c: Cardiac muscle has intercalated discs; skeletal muscle does not.

d: Cardiac muscle has 1 or 2 nuclei per cell; skeletal muscle has multiple nuclei per cell.

e: Cardiac muscle has more well-defined terminal cisternae.

A) a, c, d

B) a, c, e

C) b, c, e

D) a, b, e

E) b, d, e

36) What are the cell-to-cell contacts of the cardiac muscle fibers called?

A) Z discs

B) T-tubules

C) Intercalated discs

D) Cardiac discs

E) Sarcoplasmic reticulum

37) Myofibrils within cardiac muscle cells are aligned in sarcomeres.

38) Contrast the length-tension relationship for cardiac muscle to that which is found in skeletal muscle.  In other words, for each type of muscle, what is the optimal length?  How is such an arrangement adaptive to cardiac muscle?

39) The metabolic pathways of cardiac muscle make it

A) somewhat susceptible to heart attack, because it relies so exclusively on aerobic metabolism.

B) extremely susceptible to heart attack, because it uses such a variety of fuel sources.

C) somewhat susceptible to heart attack, because it has so few mitochondria.

D) relatively resistant to heart attack, because it uses exclusively anaerobic metabolism.

E) relatively resistant to heart attack, because it has a great capacity to accrue oxygen debt.

40) Metabolically, cardiac muscle relies on

A) aerobic metabolism using glycolysis of glycogen to meet most ATP demands.

B) aerobic metabolism using many mitochondria and a rich supply of myoglobin.

C) anaerobic metabolism using glycolytic enzymes to quickly generate ATP.

D) anaerobic metabolism using myoglobin, creatin kinase, and ketone bodies.

41) Cardiac muscle is able to use a variety of fuel types for cellular respiration.

42) The heart valves

A) stabilize and hold the arteries leaving the heart.

B) permit the passage of blood in one direction.

C) separate the right and left sides of the heart.

D) are only used in the fetal heart.

E) direct the conduction impulse through the heart muscle.

43) Which action leads to the closure of the right atrioventricular valve?

A) Contraction of the right atrium

B) Contraction of the left atrium

C) Contraction of the right ventricle

D) Relaxation of the right ventricle

E) Relaxation of the left atrium

44) How many half-moon shaped, pocketlike cusps are found in each semilunar valve?

A) 1

B) 2

C) 3

D) 4

E) 6

45) Which valve prevents the backflow of blood into the left ventricle when the ventricles relax?

A) Left atrioventricular valve

B) Aortic semilunar valve

C) Right atrioventricular valve

D) Pulmonary semilunar valve

E) None of the choices is correct.

46) As blood is pumped out of the heart and into the major arteries leaving the heart, it

A) pushes against the semilunar valves and opens them.

B) pushes against the semilunar valves and closes them.

C) fills the cusps of the semilunar valves, causing them to expand and block the backflow of blood

D) pushes against the atrioventricular valves and opens them.

E) fills the cusps of the atrioventricular valve causing opening of the bicuspid and closure of the tricuspid.

47) Typically, there are ________ papillary muscles that project from the wall of the left ventricle and attach to the tendinous cords that support the left AV valve.

A) three

B) two

C) a highly variable number of

D) six

E) no

48) Nodal cells contain fast voltage-gated calcium channels.

49) The hearts nodal cells have a more negative resting potential than neurons do, because nodal cells lack leak channels for sodium and potassium ions.

50) An autorhythmic heart cell is one in which

A) action potentials fire spontaneously.

B) action potentials are stimulated by internal stores of acetylcholine.

C) action potentials always occur at exactly the same frequency.

D) all filaments contract and relax with a high degree of synchrony.

E) action potentials are initiated by the autonomic nervous system.

51) SA nodal cells are autorhythmic.

52) Once an SA nodal cell reaches threshold, the depolarization phase occurs during which

A) potassium comes in through fast voltage-gated channels.

B) calcium comes in through fast voltage-gated channels.

C) potassium moves out through fast voltage-gated channels.

D) sodium moves out through slow voltage-gated channels.

E) calcium moves out through slow voltage-gated channels.

53) For the repolarization phase of an SA nodal cell action potential,

A) sodium and potassium channels open.

B) calcium channels open and sodium channels close.

C) calcium and potassium channels close.

D) calcium channels close and potassium channels open.

E) sodium and chloride channels open.

54) Vagal tone refers to the

A) decreasing of the heart rate below its inherent rhythm by parasympathetic stimulation.

B) decreasing of the heart rate below its inherent rhythm by sympathetic stimulation.

C) increasing of the heart rate above its inherent rhythm by sympathetic stimulation.

D) increasing of the heart rate above its inherent rhythm by parasympathetic stimulation.

55) What is the sequence of events in the transmission of an impulse through the heart muscle?

a: AV node

b: AV bundle

c: SA node

d: Through the atria

e: Through the ventricles

f: Bundle branches

g: Purkinje fibers

A) c, d, a, b, f, g, e

B) d, b, a, c, f, g, e

C) b, a, d, c, f, g, e

D) f, g, d, c, b, a, e

E) c, d, a, f, b, g, e

56) At the AV node of the conduction system, the action potential is

A) rapidly advanced due to the cells being large and well connected by gap junctions.

B) rapidly advanced due to the cells being small and well insulated by myelin.

C) delayed due to the cells being small and having few gap junctions.

D) delayed due to the cells being large and having many leakage channels.

57) The membrane of a contractile cardiac muscle cell contains

A) fast voltage-gated sodium channels and fast voltage-gated calcium channels.

B) fast voltage-gated sodium channels and slow voltage-gated calcium channels.

C) slow voltage-gated sodium channels and slow voltage-gated calcium channels.

D) slow voltage-gated sodium channels and fast voltage-gated calcium channels.

58) The membrane of a contractile cardiac muscle cell contains

A) no calcium pumps.

B) calcium pumps that move calcium out of the cell.

C) calcium pumps that move calcium into the cell.

D) calcium pumps that open and allow calcium to diffuse down its concentration gradient to reach equilibrium.

59) During the plateau phase of a cardiac muscle cell's action potential, the membrane stays

A) depolarized as potassium exits and calcium enters.

B) depolarized as potassium enters and calcium exits.

C) repolarized as sodium enters and calcium exits.

D) hyperpolarized as sodium and calcium exit.

E) hyperpolarized as potassium enters and calcium exits.

60) As with action potentials in other types of cells, the repolarization of cardiac muscle cells involves the

A) entrance of calcium through voltage-gated channels.

B) exit of potassium through voltage-gated channels.

C) entrance of sodium through voltage-gated channels.

D) binding of ACh to ACh receptor.

E) simultaneous closure of sodium channels and opening of calcium channels.

61) Most of the calcium that triggers contraction of cardiac muscle comes

A) into the cell through leakage channels in the sarcolemma.

B) into the cell through voltage-gated channels in the sarcolemma.

C) from the sarcoplasmic reticulum of the cell.

D) from the Golgi apparatus of the cell.

62) To initiate a cardiac muscle cell contraction, calcium

A) binds to calmodulin.

B) binds to troponin.

C) binds to actin.

D) binds to the Z-disc.

E) binds to tropomyosin.

63) The time that starts when a muscle cell is depolarized and ends when it is able to be restimulated is the ________ period.

64) Like skeletal muscle cells, cardiac muscle cells have an absolute refractory period prior to repolarization.

65) Which type of muscle cell exhibits a longer refractory period?

A) Cardiac muscle cell

B) Skeletal muscle cell

66) The plateau phase of an action potential

A) occurs only in skeletal muscle and makes those fibers' contractions most forceful.

B) leads to tetanic contractions in smooth and skeletal muscle.

C) allows cardiac muscle cells to contract and then relax without locking up.

D) allows cardiac muscle cells to exhibit synchronous fibrillation.

67) What part of the cardiac conduction system is located in the posterior wall of the right atrium, adjacent to the entrance of the superior vena cava?

A) AV bundle

B) Bundle branches

C) Purkinje fibers

D) AV node

E) SA node

68) The atrioventricular (AV) node is located in the

A) floor of the left atrium.

B) floor of the right atrium.

C) roof of the left ventricle.

D) back wall of the right ventricle.

E) back wall of the left ventricle.

69) In an ECG, what does the T wave represent?

A) Depolarization of the atria

B) Depolarization of the right ventricle

C) Repolarization of the ventricles

D) Closure of the AV valves

E) Depolarization of the left ventricle

70) In an EKG, the P wave is generated when the

A) ventricles depolarize.

B) atria depolarize.

C) atria repolarize.

D) ventricles repolarize.

E) Purkinje fibers initiate an impulse.

71) Which segment of the ECG reflects the plateau phase of ventricular muscle cells' action potentials?

A) P-T segment

B) S-T segment

C) Q-R segment

D) P-R interval

E) T-P interval

72) Someone with a heart block would have

A) a long P-R interval.

B) a long T-P interval.

C) a short P-R interval.

D) a short T-P interval.

73) Someone with tachyarrhythmia would be expected to show an abnormally

A) small Q-T interval.

B) large P-R interval.

C) large R-R interval.

D) high amplitude P wave.

74) During the S-T segment, what is occurring within cardiac muscle cells?

A) Sodium is rapidly diffusing out of atrial muscle cells.

B) Sodium channels are beginning to open in ventricular cells and calcium is entering through slow channels in atrial cells.

C) Calcium is entering and potassium is leaving ventricular cells.

D) Potassium is entering atrial cells and sodium is leaving ventricular cells.

75) During a cardiac cycle, how many of the four chambers contract at any one time?

A) 1

B) 2

C) 4

D) Highly variable, depending on the heart beat rate

E) None of the choices is correct.

76) During ventricular contraction

A) only the AV valves open.

B) only the AV valves close.

C) only the semilunar valves close.

D) the semilunar valves close and the AV valves open.

E) the semilunar valves open and the AV valves close.

77) The opening and closing of the heart valves is caused by

A) contraction and relaxation of papillary muscles that pull on heart strings.

B) pressure changes of alternating contraction and relaxation during the cardiac cycle.

C) contraction of the smooth muscle in the walls of the great vessels leaving the heart.

D) action potentials within the cusps of the valves.

78) Blood moves into and then out of a heart chamber because

A) it moves along its pressure gradient, and that gradient depends on contraction and relaxation during the cardiac cycle.

B) it is under constant pressure, but its movement is dictated by the control of valve openings and closures.

C) the veins and arteries constrict and dilate to propel and attract blood.

D) All of the choices are correct.

79) Atrial contraction occurs just before

A) isovolumetric relaxation.

B) atrial relaxation and ventricular filling.

C) ventricular ejection.

D) isovolumetric contraction.

80) The beginning of ventricular contraction, when all four valves are closed, is called (2 words) ________.

81) Just prior to atrial contraction,

A) all four chambers are at rest and AV valves are open.

B) all four chambers are at rest and AV valves are closed.

C) all four chambers are contracting and all valves are open.

D) both ventricles are contracting and blood is being ejected into the major arteries.

E) both atria are contracting and blood is being ejected into the major arteries.

82) Immediately prior to atrial contraction, blood continues to enter the atria from the venae cavae and pulmonary veins.

83) The shutting of the semilunar valves occurs during which phase?

A) Isovolumetric contraction

B) Ventricular ejection

C) Isovolumetric relaxation

D) Atrial contraction and ventricular filling

E) Late ventricular diastole

84) Cardiac output is the amount of blood that is pumped

A) by a single ventricle in one hour.

B) by a single ventricle in one minute.

C) by both ventricles in one hour.

D) by both ventricles in one minute.

E) by the left ventricle into the aorta in one beat.

85) Cardiac output is usually expressed in

A) beats per minute.

B) mL per beat.

C) mm Hg.

D) liters per minute.

86) Cardiac output equals the

A) end diastolic volume minus end systolic volume.

B) blood pressure multiplied by heart rate.

C) heart rate multiplied by stroke volume.

D) stroke volume divided by heart rate.

E) cardiac reserve minus the stroke volume.

87) Cardiac reserve is

A) the potential increase in stroke volume someone would show if they engaged in athletic training.

B) the increase in cardiac output an individual is capable of demonstrating during vigorous exercise.

C) the amount of blood left in the heart after the ventricle has contracted during cardiac cycles at rest.

D) the blood that the heart uses to nourish its cardiac muscle and does not put into general circulation.

88) Cardiac reserve is greater in a nonathletic individual than in a highly trained athlete.

89) A chemical that alters heart rate is known as a(n) ________ agent.

90) Large doses of certain stimulants can lead to dangerous increases in heart rates.  Such a stimulant is a

A) positive chronotropic agent.

B) negative chronotropic agent.

C) positive inotropic agent.

D) negative inotropic agent.

91) Norepinephrine is considered a positive chronotropic agent because it causes

A) less calcium to enter heart cells, which leads to lower risk of heart attack.

B) more forceful contractions during each heart rate.

C) an increase in the firing rate of SA node cells.

D) thyroid hormone to have a steadying effect on heart activity.

E) heart cell membrane potentials to become more positive during action potentials.

92) Which of the following is not one of the three main factors influencing stroke volume?

A) Afterload

B) Chronotropic agents

C) Inotropic agents

D) Venous return

93) According to the Frank-Starling law

A) the more calcium available to the heart cell, the more forcefully it will contract.

B) as the volume of blood entering the heart increases, ventricular contractions become more forceful.

C) the faster the heart rate, the larger the stroke volume.

D) the greater the resistance from the arteries, the higher the blood pressure.

94) The resistance in arteries to the ejection of blood by the heart is known as ________.

95) Preload is the stretch of the heart wall as determined by the amount of blood returned by the veins.

96) A drug that decreased calcium levels in a muscle cell and thereby lowered the number of crossbridges formed during the heart's contractions would be a

A) positive chronotropic agent.

B) negative chronotropic agent.

C) positive inotropic agent.

D) negative inotropic agent.

97) Which of the following would cause a decrease in cardiac output?

A) An increase in venous return

B) An increase in afterload

C) Addition of positive inotropic agents

D) An increase in heart rate

98) Explain the factors that affect cardiac output.  In your answer provide one example of a positive inotropic agent and one example of a positive chronotropic agent.  For each of those examples, explain what specifically happens to the cells of the heart when they have their effect.

99) Parasympathetic innervation of the heart occurs via

A) CN IV.

B) CN VI.

C) CN VIII.

D) CN X.

E) CN XII.

100) Sympathetic innervation of the heart arises from the ________ segments of the spinal cord.

A) T1–T5

B) T3–T8

C) T5–T10

D) T6–T11

E) T11–L2

101) Parasympathetic innervation influences the heart rate, but generally tends to have no direct effect on the force of contractions.

102) Sympathetic innervation of the heart

a: increases the heart rate

b: decreases the heart rate

c: increases the force of contractions

d: decreases the force of contractions

e: has no effect on contraction force

A) a, c

B) b, d

C) a, d

D) b, e

E) a, e

103) The right border of the heart is supplied by the

A) circumflex artery.

B) posterior interventricular artery.

C) anterior interventricular artery.

D) right marginal artery.

E) great cardiac vein.

104) This artery is sometimes referred to as the "widowmaker" because blockage of it often leads to fatal heart attack.  It serves the anterior heart and is more formally called the (2 or 3 words) ________ artery.

105) The left and right coronary arteries

A) are interconnected with several high-volume anastomoses allowing for well-perfused alternate blood paths.

B) are functional end arteries because the blockage of one of them leads to tissue death in the area it supplies.

106) What would you expect a cardiologist to recommend if there was substantial occlusion to a patient's left coronary artery but not the right coronary artery?

A) Because there are multiple alternate paths for blood delivery, the cardiologist would not intervene.

B) Because this is a relatively small, unimportant artery, the cardiologist would not intervene.

C) Because this is an important artery, and alternate vascular paths are inadequate, the cardiologist would treat the condition.

D) Because occlusions require blood to be moved under greater pressure, the cardiologist would prescribe drugs to raise blood pressure.

107) The posterior interventricular artery is a branch off of the

A) superior vena cava.

B) left marginal artery.

C) right coronary artery.

D) left coronary artery.

E) coronary sinus.

108) Coronary vessels are open when the heart is

A) contracting.

B) relaxed.

109) Blood flow to the heart wall courses through coronary vessels in a steady stream.

110) The great cardiac vein runs alongside the

A) anterior interventricular artery.

B) posterior interventricular artery.

C) right marginal artery.

D) aorta.

E) coronary sinus.

111) The function of the coronary sinus is to

A) connect the top and bottom halves of the heart.

B) guide the aorta out of the heart.

C) guide the inferior vena cava into the right atrium.

D) take blood from the coronary circulation to the right atrium.

E) shunt blood from the right atrium to the left atrium.

112) Which vein drains the posterior aspect of the ventricles of the heart?

A) Great cardiac vein

B) Middle cardiac vein

C) Small cardiac vein

D) Circumflex vein

113) Which prenatal structure forms the ascending aorta and pulmonary trunk?

A) Truncus arteriosus

B) Sinus venosus

C) Primitive atrium

D) Primitive ventricle

E) Conus cordis

114) The foramen ovale of the fetal heart is an opening in the

A) interventricular septum.

B) interatrial septum.

C) fossa ovalis.

D) aorticopulmonary septum.

E) tetralogy of Fallot.

115) The tetralogy of Fallot is

A) a condition in which the left and right sides of the heart are completely reversed.

B) a developmental disorder that is a cardiac septal defect.

C) an exceptionally fast heart rate.

D) an inadequate cardiac output due to poorly contracting heart chambers.

E) occlusion of the left coronary artery.

116) In this figure showing an anterior view of the heart, the left atrium is noted by number

A) 1.

B) 2.

C) 3.

D) 4.

E) 5.

117) In this figure showing an anterior view of the heart, what is depicted by number 7?

A) Aortic semilunar valve

B) Right atrium

C) Left ventricle

D) Right atrioventricular valve

E) Pulmonary semilunar valve

118) All of the heart's sulci house blood vessels that supply the myocardium.

119) The left ventricle walls are typically thicker than the right ventricular wall.

120) It is the contraction of the atria during atrial systole that completes the filling of the ventricles while the ventricles are in diastole.

121) About 70% of the ventricle filling is achieved passively without the contraction of the atria.

122) During ventricular contraction, the semilunar valves close in order to permit the blood to enter the large arterial trunks that carry blood away from the heart.

123) Though the autonomic innervation by autonomic centers in the brainstem cannot initiate a heartbeat, it can increase or decrease the heart rate.

124) Purkinje fibers are small fibers within the atria that conduct impulses rapidly.

125) The middle layer of the heart wall that is made of cardiac muscle tissue is the ________.

126) The numerous ________ within the intercalated discs prevent cardiac muscle fibers from pulling apart.

127) The anterior part of each atrium is a flaplike extension called a(n) ________.

128) The inferior chambers of the heart are called ________.

129) The property that allows the heart to initiate each heartbeat itself is called ________.

130) The heartbeat is initiated by the cells of the ________ node.

131) ________ innervation increases the rate and the force of heart contraction.

132) The connections shared by arteries that allow them to shunt blood from one artery to another are called ________.

133) The ________ cardiac vein travels alongside the right marginal artery.

134) The term used to describe the inadequate blood flow to a structure caused by obstruction of the blood supply is ________.

135) Normally, the left and right ventricles eject the same amount of blood.

136) If the stroke volume is unequal between the left and right ventricles, ________ may occur, which is excess fluid surrounding or within cells.

137) The atrial reflex relies upon chemoreceptors to detect stretch in the atrial wall.

138) Parasympathetic and sympathetic influence on heart rate is controlled by reflexes.

139) Select all that occur during the plateau phase of an action potential on a cardiac muscle cell.

A) Calcium is entering the cell.

B) Potassium is exiting the cell.

C) Sodium is entering the cell.

D) Calcium is exiting the cell.

140) Around day 21 of development the primitive heart begins to beat. At this stage it contains the four chambers: two atria and two ventricles.